He is definitely fishing for sympathy, but Barb does rely on him and his tugboat to help out. Their finances are intrinsically linked. Even if the thousand dollars goes straight to lego, that could mean that less of the next tugboat goes to lego and more to Barb or something similar. The way I interpret his comments, Barb has been riding his ass about money. He sees getting this $1000 as a way of getting her off his ass, presumably by adding to/becoming less of a drain on their shared resources
When there was discussion of the post-fire gift, people said that there should be only gift cards to stores that wouldn't sell him vidya or lego. I pointed out that if we gave him food and clothes, that would just free up more of the tugboat for vidya and legos. I think the same principle applies here. I am sure it would buy a bunch of lego, but I think it would also relieve some of the other financial stress him and Barb are under.